Hammer Perpetuem. Taking a few packs with me on tour starting next weekend. One will certainly be used for a 55 mile, three pass (one of which is dirt and quite steep in places) day with only one place for food along the way that will likely be closed when I get to that area. But be careful. If it's really hot out, the stuff only lasts a few hours. After that, it can turn your stomach. Don't ask me how I know.
I also like Hammer gels.